Design and manufacturing technology for electronic and optical components has advanced and continues to advance in miniaturization, density, function and performance. As a result, today's devices and systems incorporate a large amount of functionality into a small amount of space. Examples of this are laptop computers, servers, switches and other small form factor devices and systems. These systems must be kept from overheating by dissipating heat to the surrounding environment. Some components within the systems must also be given special attention because they generate more heat than the others. Examples of these devices may include microprocessors, optical transceivers, power converters and many other components.
Conventionally, components within a system which generate large amounts of heat are cooled by mounting a heat sink on the components themselves. In this configuration, the heat sink is generally mounted to the device by adhering or clipping it to the device which dissipates heat. The adhering agent is generally thermally conductive and facilitates the flow of heat from the device to the heat sink where the heat is exchanged with the surrounding environment through radiation and convection.
Adhesives and clips, however, are not well suited for mounting heat sinks in a variety of situations. First, electronic components may be packaged in Teflon or nylon packages. Adhesives do not adhere well to Teflon and nylon and therefore the application of adhesive to attach a heat sink to such components does not work well and is unreliable. Similarly, clipping a heat sink to a device may not be stable and, depending on the density of the layout within a system, may not fit.
As an alternative to mounting a heat sink on a device through adhesives or clips, heat sinks have conventionally also been mounted to a substrate such as a printed circuit board, to which the device is attached. In this configuration, standoffs or posts are generally required to support or suspend the heat sink above the substrate. These supports require additional space on the substrate and also generally require through holes in the substrate itself. For this reason, heat sinks generally cannot be added to a preexisting substrate design without redesigning the substrate to accommodate the supports. In addition, for newly designed substrates, the through holes place in the substrate to accommodate the posts block wiring channels within the substrate and therefore may complicate layout of the substrate. In addition, the posts themselves take up valuable space on the substrate that could be used for other purposes.
Accordingly, there is a need for a method and apparatus for mounting a heat sink in an operative relation to an electronic device that overcomes alignment difficulties and is easy to manufacture. There is a further need for a method and apparatus for mounting a heat sink that does not require additional area on a substrate, such as a printed circuit board. There is a further need for a heat sink that does not require adhesives or additional structures such as mounting posts for affixing the heat sink to a substrate.